1. Field of the Invention
The present invention relates generally to exchanging of a die half mounted on a die mounting board of an injection molding machine. More particularly, the present invention relates to a method of automatically exchanging a stamper unit for injection-molding a compact disc, a video disc or the like with another one. Further, the present invention relates to an automatic exchanging apparatus for practicing a method of the foregoing type.
2. Background Art
Conventionally, a die half for injection-molding a disc or the like is designed in the form of a unit which assures that the present stamper having certain information recorded therein can be exchanged with another stamper having different information recorded therein for performing an injection-molding operation to produce other type of discs or the like. A stamper unit (i.e., a die half having a stamper fitted into a cavity surface thereof) is usually designed with small dimensions and its weight is low enough to allow it to be carried directly by an operator. For this reason, exchanging of a used stamper unit with a new one can be achieved manually while they are placed on a side table located sideward of a die mounting board of an injection molding machine.
In the conventional case as mentioned above, since each stamper unit is handled directly with the operator's hands by carrying it to the side table and then receiving another stamper unit for the purpose of stamper unit exchanging, occasionally a malfunction arises that in a stamper unit is damaged or injured during the foregoing handling, resulting in the stamper unit failing to be practically used for injection-molding operations.
To cope with the foregoing malfunction, a cover or the like is placed on the stamper side of each stamper unit. In practice, however, the cover is often removed from the stamper unit before the present stamper unit is exchanged with a new one. In the circumstances as mentioned above, there is recognized a tendency that the cover is restrictively used at the time of conveyance of each stamper unit.